Hospitalisation rates among patients with primary Sjögren’s syndrome: a population-based study, 1995–2016

Objective To determine rates and primary discharge diagnoses of hospitalisation in a cohort of patients with incident primary Sjögren's syndrome (pSS) compared with the general population. Methods This was a retrospective population-based cohort study focused on Olmsted County, Minnesota. The pSS cohort consisted of patients with incident pSS in the 1976-2015 period and was compared with a cohort of individuals without pSS matched 3:1 for age, sex and calendar year, randomly selected from the same population. Hospitalisations in 1995-2016 were examined. Discharge diagnoses were categorised using the Clinical Classifications Software for International Classification of Diseases, 9th revision, Clinical Modification. Results A total of 385 hospitalisations occurred in the 160 patients with pSS during 1592 person-years of follow-up. Among 466 comparators, there were 899 hospitalisations during 4660 person-years of follow-up, resulting in a significantly higher rate of hospitalisations in patients with pSS (rate ratio (RR): 1.25, 95% CI: 1.11 to 1.41). Rates of hospitalisation were increased among patients with pSS for endocrine, nutritional and metabolic diseases and immunity disorders (RR 1.82, 95% CI 1.08 to 2.98), diseases of the musculoskeletal system and connective tissue (RR 1.49, 95% CI 1.05 to 2.05) and for injuries and poisoning (RR 1.46, 95% CI 1.01 to 2.06). While not significantly increased overall, hospitalisations for diseases of the circulatory system were significantly increased in patients with pSS aged ≥75 years (RR 1.54, 95% CI 1.11 to 2.11). Conclusions Patients with pSS experienced higher rates of hospitalisation than the general population. Hospitalisations for endocrine/metabolic disorders, diseases of the circulatory system, diseases of the musculoskeletal system and connective tissue disorders, and injuries were more common among patients with pSS than comparators.